Left Ventricular Assist Device (LVAD) Specialized Centers of Clinically Orientated Research (SCCOR) Coagulation - Acute Intrinsic Pathway Antagonist (IPA)

Exclusion Criteria

• •Evidence of active bleeding within 24 hours prior to randomization
• •History of a platelet disorder, including but not limited to thrombocytopenia and thrombasthenia
• •Thrombocytopenia with platelets \<80,000/ml within 48 hours prior to randomization
• •History of an inherited or acquired coagulation disorder
• •Hemoglobin \<8 g/dL (4.85 mmol/L) or hematocrit \<26% within 24 hours prior to randomization
• •Clinical indication for (or the intention to use) standard anticoagulation therapy at time of randomization (e.g., atrial fibrillation or DVT)
• •Intention to treat with more than 325 mg aspirin daily
• •Any clinical requirement or intention to treat with phenytoin, tolbutamide or warfarin post randomization
• •RVAD support at the time of randomization
• •Estimated glomerular filtration rate (GFR) ≤30 ml/min (by Cockcroft-Gault formula), or any form of dialysis within 48 hours prior to randomization
• •Evidence of intrinsic hepatic disease as defined as biopsy proven liver cirrhosis; or liver enzyme values (AST or ALT) that are \>3 times the upper limit of normal; or Total Bilirubin \>1.5 times the upper limit of normal (with the exception of Gilbert's Syndrome) within 3 days prior to randomization
• •Active systemic infection, in the judgment of the investigator, within 3 days prior to randomization
• •Stroke or transient ischemic attack (TIA) within 6 months prior to randomization
• •History of intracranial hemorrhage or gastrointestinal bleed within 3 months prior to randomization
• •Alzheimer's disease, or any other form of irreversible dementia
• •History of psychiatric disease (including drug or alcohol abuse) that may impair compliance with the study protocol
• •Pregnant or breastfeeding at time of randomization
• •Received investigational intervention within 30 days prior to randomization
• •Body weight \< 45 Kg